Cross-arc groove magnetorheological clutch squeezed by electromagnetic force

Abstract

The present invention discloses a cross arc groove magnetorheological clutch squeezed by electromagnetic force, comprising a driving shaft, a driven housing and a driven shaft, wherein the driven housing comprises a left housing, a driven cylinder, an armature and a cover, a coil groove is provided in the middle of the inner side of the driven cylinder, and an excitation coil is wound in the coil groove; the part of the driving shaft located in the driven housing forms a transmission section, a driving disc and a driven disc are sleeved on the transmission section, and magnetorheological fluid is filled in the gap between the left housing, the driving disc, the driven disc and the armature; the left end of the driven shaft is fixedly connected to the cover, a support ring is also sleeved on the driven shaft, a plurality of guide support rods are provided on the left side of the support ring, and a shape memory alloy spring is sleeved on the guide support rod. The present invention can improve the maximum torque transmitted by the clutch, and effectively solve the problem that the performance of the magnetorheological fluid decreases with the increase of the ambient temperature, thereby ensuring the stability of the clutch transmission performance, and has a simple structure.

Description

Technical Field

[0001] The invention relates to the technical field of clutches, and in particular to a cross arc groove magnetorheological clutch extruded by electromagnetic force. Background Art

[0002] Shape memory alloy is a new type of intelligent material. After a certain degree of deformation under certain conditions, the shape memory alloy with a certain initial shape will undergo reverse deformation by appropriately changing the temperature, so that the material returns to its initial shape. In the process of shape recovery, if the shape memory alloy is constrained, it will generate a large restoring force, and its restoring force can be used to do external work; magnetorheological fluid is a two-phase suspension that can change from a fluid to a solid or gel-like state under the action of an external magnetic field. The change of magnetorheological fluid is reversible. Under the action of an external magnetic field, the magnetically polarized particles can form a dipole moment, so that the particles form a chain-like or columnar structure parallel to the direction of the magnetic field, resulting in a change in the phase state of the magnetorheological fluid, an increase in the apparent viscosity of the magnetorheological fluid, and a very high yield stress, which can be used to transmit torque.

[0003] However, in the prior art, for example, CN109611464B discloses a disc cam squeeze clutch based on magnetorheological fluid. When the electromagnetic coil is energized, the disc cam squeezes the piston head to move rightward, squeezing the magnetorheological fluid in the multi-stage interlayer cavity from a liquid-like state to a solid-like state, thereby solving the jitter and impact problems of the automobile clutch when transmitting force and torque; for example, CN109538649B discloses an axially movable squeeze multi-layer cylinder clutch based on magnetorheological fluid. When the motor rotates, the inner shaft of the output shaft is driven to move axially, so that the length and adjacent area of ​​the annular cavity formed by the input shaft and the output shaft change. When the piston head is affected by the magnetic field force and moves to the left, the magnetorheological fluid in the annular cavity is squeezed, thereby improving the clutch's ability to transmit force and torque; for example, CN206802225U discloses a magnetorheological fluid and friction combined transmission device squeezed by a shape memory alloy. When the ambient temperature rises, the device can switch the shape memory alloy to change the shape memory alloy. The power supply is automatically turned on. After the temperature of the device rises, the shape memory alloy spring generates an output force to push the driven pressure plate and the active right housing to generate pressure. The driven pressure plate can also squeeze the magnetorheological fluid, which can increase the performance of the magnetorheological fluid. For example, CN103277471B discloses an alternating transmission device of magnetorheological fluid and memory alloy, which uses the characteristics of memory alloy in sensing temperature to make up for the deficiency of magnetorheological fluid transmission device performance degradation or even failure at high temperature, so that the magnetorheological fluid transmission device can meet the working requirements at different temperatures, and realize the alternating transmission of magnetorheological fluid and memory alloy by sensing temperature; for example, CN104895956A discloses an electrothermal magnetic shape memory alloy and magnetorheological fluid composite centrifugal clutch, which uses the friction between the disc magnetorheological fluid and the centrifugal slider to jointly transmit torque, and changes the magnetic field of the excitation coil acting on the magnetorheological fluid and the temperature of the shape memory alloy spring by changing the current size, thereby realizing intelligent control of the clutch transmission torque.

[0004] At present, researchers have conducted a lot of research on the individual applications of shape memory alloys and magnetorheological fluids in the field of transmission, but there is still little research on the joint application of shape memory alloys and magnetorheological fluids in transmission devices, especially the research on magnetorheological transmission jointly extruded by electromagnetic and shape memory alloy springs. At present, the torque transmitted by a single magnetorheological clutch is small, the transmission efficiency is low, and the magnetorheological fluid transmission performance decreases with the increase of temperature, resulting in poor torque transmission stability. Although the combined transmission of shape memory alloys and magnetorheological fluids can improve the transmission torque, how to better apply shape memory alloys and magnetorheological fluids to clutches in transmission, reasonably utilize the extrusion strengthening effect of magnetorheological fluids, solve the performance degradation of magnetorheological fluids with the increase of ambient temperature, reduce the wall slip of magnetorheological fluids, and improve the transmission stability and effect of clutches have become technical problems that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a cross-arc groove magnetorheological clutch extruded by electromagnetic force, which can effectively combine shape memory alloy and magnetorheological fluid into the clutch, thereby effectively solving the problem that the performance of magnetorheological fluid decreases with the increase of ambient temperature; and reasonably applying the extrusion strengthening effect of magnetorheological fluid, reducing the wall slip of magnetorheological fluid, improving the maximum torque transmitted by the clutch, and ensuring the transmission stability and transmission performance of the clutch.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a cross arc groove magnetorheological clutch squeezed by electromagnetic force, comprising a driving shaft, a driven housing and a driven shaft, characterized in that: the driven housing comprises a left housing, a driven cylinder, an armature and a blind cover, and the left housing is fixedly connected to the left end of the driven cylinder; the armature is located at the right end of the driven cylinder, and the middle part thereof protrudes to the right to form a sleeve, and the armature is sleeved on the blind cover through the sleeve, and is connected to the blind cover by sliding cooperation with the key and the keyway; on the left side of the armature, a plurality of guide shear rods are arranged around the driven cylinder corresponding to the position thereof, and a guide hole is arranged on the right end face of the driven cylinder corresponding to the guide shear rod, one end of the guide shear rod is fixedly connected to the armature, and the other end extends into the guide hole and is connected to the guide hole by sliding cooperation;

[0007] A coil groove is provided in the middle of the inner side of the driven cylinder, and an excitation coil is wound in the coil groove; a magnetic isolation ring is provided on the inner side of the driven cylinder, the outer side of the magnetic isolation ring is in close contact with the inner side of the driven cylinder, the left end of the magnetic isolation ring is in close contact with the left shell, and the right end extends from the right end of the driven cylinder; a circular groove is provided on the left side of the armature corresponding to the magnetic isolation ring, and the depth of the circular groove is greater than or equal to the length of the magnetic isolation ring extending from the right end of the driven cylinder; the right end of the magnetic isolation ring extends into the circular groove and is connected with the groove wall of the circular groove in a sliding fit;

[0008] The right end of the driving shaft passes through the left housing and then extends into the cover, and is connected to the left housing and the cover through a bearing; the part of the driving shaft located in the driven housing forms a transmission section, and the transmission section is provided with a plurality of keyways around it, so that the transmission section forms a spline shaft; a driving disc and a driven disc are sleeved on the transmission section, and the driving disc and the driven disc are alternately distributed along the axial direction of the driving shaft, and there is a gap between adjacent driving discs and driven discs, and there is also a gap between the driving disc or the driven disc and the left housing and the right housing; wherein the inner hole of the driving disc is a spline hole corresponding to the transmission section, and the driving disc is connected to the transmission section through the spline hole and can rotate synchronously with the driving shaft; the inner hole of the driven disc is a circular hole and can rotate freely around the driving shaft; a plurality of arc grooves are provided on both sides of the driving disc and the driven disc, and the arc grooves are distributed at a plurality of positions corresponding to the driving disc and the driven disc. Two adjacent arc grooves radially distributed along the driving disk or the driven disk are staggered on a circumference with the center of the driven disk or the driven disk as the center; an inner rubber ring is respectively provided between the driving disk and the left housing, between two adjacent driving disks, and between the driving disk and the armature, and the inner rubber ring is sleeved on the transmission section, and a gap is provided between the outer side of the inner rubber ring and the inner hole of the driven disk; an outer rubber ring is respectively provided between the driven disk and the left housing, between two adjacent driven disks, and between the driven disk and the armature, and the outer side of the outer rubber ring is tightly attached to the magnetic isolation ring, and a gap is provided between the inner side and the outer edge of the driving disk; the driven disk and the outer rubber ring are connected to the left housing by several connecting bolts that penetrate the outer rubber ring and the driven disk from right to left in sequence; the gaps between the left housing, the driving disk, the driven disk, and the armature are filled with magnetorheological fluid;

[0009] The left end of the driven shaft is fixedly connected to the blind cover, and a support ring is also sleeved on the driven shaft, and the support ring is fixedly connected to the blind cover; a plurality of guide support rods are provided on the left side of the support ring, and the length direction of the guide support rods is consistent with the axial direction of the driving shaft; a shape memory alloy spring is sleeved on the guide support rod, and one end of the shape memory alloy spring is fixedly connected to the armature, and the other end is in contact with the support ring.

[0010] Furthermore, on the left side of the armature, corresponding to the position of the driven cylinder, several return springs are arranged around it. On the right end face of the driven cylinder, a spring groove is provided corresponding to the return spring. The return spring is located in the spring groove, one end of which is fixedly connected to the bottom of the spring groove, and the other end extends out of the spring groove and is fixedly connected to the armature.

[0011] Furthermore, a brush slip ring is provided on the left side of the left housing. The brush slip ring is arranged coaxially with the driving shaft and is fixedly connected to the left housing. Both ends of the excitation coil are connected to the brush slip ring.

[0012] Furthermore, it also includes a dust cover, which is a cylindrical structure with one end open and the other end closed. The closed end of the dust cover has a mounting hole, and is sleeved on the driven shaft through the mounting hole. The open end of the dust cover extends toward the driven cylinder and is sleeved on the driven cylinder.

[0013] Furthermore, through holes for the screw rod of the connecting bolt to pass through are opened on the outer rubber ring and the driven plate at positions corresponding to the connecting bolts, wherein the through hole on the outer rubber ring between the driven plate and the armature is a countersunk hole, and the bolt head of the connecting bolt is located in the countersunk hole.

[0014] Furthermore, a sealing ring is respectively provided on the inner side of the two bearings. The sealing ring is sleeved on the driving shaft and seals the gap between the driving shaft and the left housing and the gap between the driving shaft and the blind cover.

[0015] Furthermore, a sealing ring is provided between the armature and the blind cover, and the sealing ring is sleeved on the blind cover and fixedly connected to the blind cover.

[0016] Furthermore, a transparent cover is provided on the left side of the left shell body. The transparent cover is sleeved on the main shaft and fixedly connected to the left shell body. A felt ring is provided between the transparent cover and the driving shaft.

[0017] Furthermore, a liquid injection hole is provided on the left shell body, and a liquid injection screw plug is provided in the liquid injection hole.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The magnetorheological fluid working gap formed by the alternating arrangement of multiple active plates and driven plates makes the clutch structure compact and the magnetorheological fluid contact area larger. In addition, cross arc grooves are processed on both sides of the active plate and the driven plate to prevent the radial wall slip effect between the magnetorheological fluid and the active plate and the driven plate, thereby increasing the shear stress of the magnetorheological fluid and effectively improving the maximum torque transmitted by the clutch.

[0020] 2. When the excitation coil is energized, the electromagnetic force generated by the excitation coil attracts the armature, and the armature squeezes the magnetorheological fluid along the axial direction of the driven shaft, increasing the pressure between each active plate and driven plate and the magnetorheological fluid, thereby enhancing the squeezing strengthening effect of the magnetorheological fluid as the magnetic field increases, further improving the transmission power of the clutch.

[0021] 3. When the temperature rises, the shape memory alloy spring stretches and generates thrust (extrusion) on the armature, causing the armature to generate greater extrusion force between the active and driven plates and the magnetorheological fluid, further enhancing the extrusion strengthening effect. This effectively ensures the transmission performance of the clutch under different temperature conditions, compensates for the decline in performance of the magnetorheological fluid as the temperature rises, and enables the clutch to transmit greater torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention.

[0023] Figure 2 Schematic diagram of the distribution structure of the active disc and the driven disc.

[0024] Figure 3 , Figure 4 It is a cloud diagram of strain distribution during the working process of the clutch in one embodiment of the present invention.

[0025] In the figure: 1-driving shaft, 2-driven shaft, 3-left housing, 4-driven cylinder, 5-armature, 6-cover, 7-guide shear rod, 8-excitation coil, 9-magnetic isolation ring, 10-driving disk, 11-driven disk, 12-inner rubber ring, 13-outer rubber ring, 14-magnetorheological fluid, 15-support ring, 16-guide support rod, 17-shape memory alloy spring, 18-reset spring, 19-brush slip ring, 20-dust cover, 21-sealing ring, 22-sealing ring, 23-transparent cover, 24-liquid injection plug. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] Example: See Figure 1 , Figure 2 , a cross arc groove magnetorheological clutch squeezed by electromagnetic force, comprising a driving shaft 1, a driven housing and a driven shaft 2; wherein the driven housing comprises a left housing 3, a driven cylinder 4, an armature 5 and a cover 6. The left housing 3 and the left end of the driven cylinder 4 are fixedly connected; the armature 5 is located at the right end of the driven cylinder 4, and the middle part thereof protrudes to the right to form a sleeve, and the armature 5 is sleeved on the cover 6 through the sleeve, and is connected to the cover 6 by sliding cooperation through the key and the keyway; when implemented, the cover 6 has a guide cylinder on the left side, and the armature 5 is sleeved on the guide cylinder, and is connected to the guide cylinder by sliding cooperation through the key and the keyway, and can drive the guide cylinder (cover 6) to rotate synchronously. A sealing ring 22 is also provided between the armature 5 and the cover 6, and the sealing ring 22 is sleeved on the cover 6 and is fixedly connected to the cover 6, so as to make the sealing effect in the driven housing better; when assembled, the sealing ring 22 is located at the inner end of the guide cylinder. On the left side of the armature 5, a plurality of guide shear rods 7 are arranged around the driven cylinder 4 at the corresponding position thereof, and on the right end face of the driven cylinder 4, a guide hole is arranged corresponding to the guide shear rod 7, one end of the guide shear rod 7 is fixedly connected to the armature 5, and the other end extends into the guide hole and is connected with the guide hole in a sliding fit. In this way, the driven cylinder 4 can drive the armature 5 to rotate synchronously through the guide shear rod 7.

[0028] A coil groove is provided in the middle of the inner side of the driven cylinder 4, and an excitation coil 8 is wound in the coil groove. A magnetic shielding ring 9 is provided on the inner side of the driven cylinder 4, and the outer side of the magnetic shielding ring 9 is in close contact with the inner side of the driven cylinder 4, and its left end is in close contact with the left shell 3, and the right end extends from the right end of the driven cylinder 4. On the left side of the armature 5, a circular groove is provided corresponding to the magnetic shielding ring 9, and the depth of the circular groove is greater than or equal to the length of the magnetic shielding ring 9 extending out of the right end of the driven cylinder 4; the right end of the magnetic shielding ring 9 extends into the circular groove and is connected with the groove wall of the circular groove in a sliding fit; wherein, during the sliding process of the armature 5 along the guide cylinder, it is always in close contact with the magnetic shielding ring 9; thereby, a closed chamber is always formed between the left shell 3, the magnetic shielding ring 9 and the armature 5. A brush slip ring 19 is also provided on the left side of the left housing 3. The brush slip ring 19 is coaxially arranged with the driving shaft 1 and fixedly connected to the left housing 3. Both ends of the excitation coil 8 are connected to the brush slip ring 19, so as to facilitate power supply to the excitation coil 8.

[0029] The right end of the driving shaft 1 passes through the left housing 3 and then extends into the blind cover 6 (the guide cylinder thereof), and is connected to the left housing 3 and the blind cover 6 (the guide cylinder thereof) through a bearing. A transparent cover 23 is also provided on the left side of the left housing 3, and the transparent cover 23 is sleeved on the main shaft and fixedly connected to the left housing 3. A felt ring is provided between the transparent cover 23 and the driving shaft 1, so as to close the gap between the left side of the left housing 3 and the driving shaft 1. A sealing ring 21 is provided on the inner side of the two bearings, respectively, and the sealing ring 21 is sleeved on the driving shaft 1, and seals the gap between the driving shaft 1 and the left housing 3 and the gap between the driving shaft 1 and the blind cover 6 (the guide cylinder thereof), so as to further improve the sealing effect of the entire clutch.

[0030] The part of the driving shaft 1 located in the driven housing forms a transmission section, and a plurality of keyways are arranged around the transmission section to form a spline shaft. A driving disk 10 and a driven disk 11 are sleeved on the transmission section, and the driving disk 10 and the driven disk 11 are alternately distributed along the axial direction of the driving shaft 1, and there is a gap between adjacent driving disks 10 and driven disks 11, and there is also a gap between the driving disk 10 or the driven disk 11 and the left housing 3 and the right housing. Among them, the inner hole of the driving disk 10 is a spline hole corresponding to the transmission section, and the driving disk 10 is connected to the transmission section through the spline hole and can rotate synchronously with the driving shaft 1. At the same time, the driving disk 10 can move along the axial direction of the driving shaft 1. The inner hole of the driven disk 11 is a circular hole and can rotate freely around the driving shaft 1. An inner rubber ring 12 is provided between the active disk 10 and the left housing 3, between two adjacent active disks 10, and between the active disk 10 and the armature 5. The inner rubber ring 12 is sleeved on the transmission section, and there is a gap between the outer side of the inner rubber ring 12 and the inner hole of the driven disk 11; an outer rubber ring 13 is provided between the driven disk 11 and the left housing 3, between two adjacent driven disks 11, and between the driven disk 11 and the armature 5. The outer side of the outer rubber ring 13 is in close contact with the magnetic isolation ring 9, and there is a gap between the inner side and the outer edge of the active disk 10. By providing the inner rubber ring 12 and the outer rubber ring, the gaps of each active disk 10 or driven disk 11 are sealed, and the extrusion force is transmitted through coordinated deformation. The driven disc 11 and the outer rubber ring 13 are connected to the left housing 3 through several connecting bolts that penetrate the outer rubber ring 13 and the driven disc 11 from right to left in sequence; in this way, the driven disc 11 can drive the left housing 3 to rotate synchronously through the connecting bolts, and then drive the driven housing to rotate synchronously. The gaps between the left housing 3, the active disc 10, the driven disc 11 and the armature 5 are filled with magnetorheological fluid 14. A liquid injection hole is also provided on the left housing 3, and a liquid injection plug 24 is provided in the liquid injection hole to facilitate the injection or replacement of the magnetorheological fluid 14.

[0031] A plurality of arc grooves are arranged on both sides of the active disk 10 and the driven disk 11. The arc grooves are distributed on a plurality of circles centered on the center of the active disk 10 or the driven disk 11, and two adjacent arc grooves radially distributed along the active disk 10 or the driven disk 11 are staggered. In this way, the contact surface between the active disk 10 and the driven disk 11 and the magnetorheological fluid 14 is non-planar, so that the friction force formed during the working process can be greatly increased, thereby increasing the transmission of torque. At the same time, the above structure makes the surface of the active disk 10 and the driven disk 11 present a mesh texture; it can prevent the radial wall slip effect between the magnetorheological fluid 14 and the active disk 10 and the driven disk 11, thereby increasing the shear stress of the magnetorheological fluid 14, and then can greatly improve the transmission of torque and increase the speed regulation range. In a specific implementation, through holes for the screw rod of the connecting bolt to pass through are opened on the outer rubber ring 13 and the driven plate 11 at positions corresponding to the connecting bolts; wherein the through hole on the outer rubber ring 13 between the driven plate 11 and the armature 5 is a countersunk hole, and the bolt head of the connecting bolt is located in the countersunk hole; in this way, interference between the bolt head of the connecting bolt and the armature 5 can be effectively avoided, thereby ensuring that the armature 5 can move freely and can squeeze the magnetorheological fluid 14 during the movement.

[0032] The left end of the driven shaft 2 is fixedly connected to the cover 6. When implemented, the driven shaft 2 and the cover 6 are formed as one body, so that the strength and stability of the driven shaft 2 and the cover 6 can be improved. During the assembly process, the driving shaft 1, the driven shaft 2 and the driven cylinder 4 are arranged coaxially, so that the stability of the clutch operation can be ensured. A support ring 15 is also sleeved on the driven shaft 2, and the support ring 15 is fixedly connected to the cover 6. A plurality of guide support rods 16 are provided on the left side of the support ring 15, and the length direction of the guide support rods 16 is consistent with the axial direction of the driving shaft 1; a shape memory alloy spring 17 is sleeved on the guide support rod 16, and one end of the shape memory alloy spring 17 is fixedly connected to the armature 5, and the other end is in contact with the support ring 15. On the left side of the armature 5, corresponding to the position of the driven cylinder 4, a plurality of return springs 18 are arranged around the driven cylinder 4. On the right end face of the driven cylinder 4, a spring groove is arranged corresponding to the return spring 18. The return spring 18 is located in the spring groove, one end of which is fixedly connected to the bottom of the spring groove, and the other end extends out of the spring groove and is fixedly connected to the armature 5. In specific implementation, the return spring 18 and the guide shear rod 7 are alternately distributed around the circumference of the driven cylinder 4. In the initial state, under the action of the return spring 18, there is a gap between the armature 5 and the right end of the driven cylinder 4; when the electromagnetic force generated by the excitation coil 8 and the squeezing of the shape memory alloy spring 17 on the armature 5 are reduced or disappear, the return spring 18 can quickly push the armature 5 back to the initial position, thereby improving the response speed of the clutch.

[0033] It also includes a dust cover 20, which is a cylindrical structure with one end open and the other end closed. The closed end of the dust cover 20 has a mounting hole, and is sleeved on the driven shaft 2 through the mounting hole. The open end extends toward the driven cylinder 4 and is sleeved on the driven cylinder 4. By setting the dust cover 20, dust can be effectively prevented from entering the clutch, thereby improving the working stability of the clutch.

[0034] During work:

[0035] 1. In the initial state, the magnetorheological fluid 14 is in the working gap formed by the active disk 10, the driven disk 11 and the driven housing, the excitation coil 8 is not energized, the active shaft 1 rotates, and the torque transmitted by the viscosity of the zero magnetic field of the magnetorheological fluid 14 cannot drive the driven housing and the driven shaft 2 to rotate.

[0036] 2. After the excitation coil 8 is energized, the magnetic flux generated by the excitation coil 8 acts on the magnetorheological fluid 14, and the magnetic particles in the magnetorheological fluid 14 are arranged in a chain structure along the direction of the magnetic flux (i.e., the magnetorheological fluid 14 solidifies). Relying on the shear stress of this chain structure, the active disk 10 drives the driven disk 11 to rotate, and the driven disk 11 drives the driven housing to rotate, thereby causing the transmitted torque to drive the driven shaft 2 to rotate, and the torque increases with the increase of current. At the same time, when the excitation coil 8 is energized, the electromagnetic force generated by the excitation coil 8 attracts the armature 5, and the armature 5 squeezes the magnetorheological fluid 14 along the axial direction of the active shaft 1. Since the active disk 10 and the driven disk 11 are separated by rubber rings, the rubber rings are deformed in coordination under the extrusion action, so that the pressure between each active disk 10, the driven disk 11 and the magnetorheological fluid 14 increases, that is, the magnetorheological fluid 14 in the working gap is squeezed, and the extrusion strengthening effect of the magnetorheological fluid 14 is enhanced with the increase of the magnetic field, further improving the transmission power of the clutch. For example, when the coil is energized and the extrusion force is 2000N, Figure 3 The deformation of the solid-like magnetorheological fluid 14 in each gap shown is basically the same; Figure 4As shown, from one end of the armature 5 to the left, the extrusion stresses of the magnetorheological fluid 14 in each gap are 54, 42, 43, 38, 38, 40, 45, 35, and 54 kPa respectively. It can be seen from the analysis that under the extrusion of the armature 5, the magnetorheological fluid 14 in each gap can produce similar extrusion strengthening effects. When the magnetic particles in the magnetorheological fluid 14 reach magnetic saturation, the magnetorheological fluid 14 reaches the maximum shear yield stress of 44 kPa, but because the electromagnetic force attracts the armature 5 to squeeze the magnetorheological fluid 14, the chain structure of the magnetorheological fluid 14 changes, and the shear yield stress of the magnetorheological fluid 14 can continue to increase. Taking the extrusion strengthening effect produced by the above-mentioned 2000N extrusion force as an example, from one end of the armature 5 to the left, the maximum shear yield stress of the magnetorheological fluid 14 in each gap is increased to 58.9, 53.8, 55.3, 53.5, 54.8, 56.1, 53.4, and 58.9 kPa respectively. Since the torque transmitted by the magnetorheological fluid 14 is linearly related to the shear stress of the magnetorheological fluid 14, and when the magnetorheological fluid 14 in the clutch undergoes shear flow, the torque of the magnetorheological fluid 14 in each gap under the extrusion condition is increased by 33.7, 24.5, 27.6, 20.5, 24.5, 27.6, 21.4, and 33.7% respectively compared with that when not extruded, so the torque transmitted by the clutch in the extrusion state is increased by 26.9%.

[0037] 3. When the clutch is engaged to transmit a large torque, cross arc grooves are processed on both sides of the active disk 10 and the driven disk 11, which increases the contact area between the magnetorheological fluid 14 and the disk, and reduces the radial wall slip of the chain-like microstructure of the magnetorheological fluid 14 under the centrifugal force after the magnetorheological fluid 14 is solidified, thereby enhancing the solidification strength of the magnetorheological fluid 14, increasing the power transmitted by the magnetorheological fluid 14, and improving the transmission efficiency of the torque.

[0038] 4. The continuous operation of the clutch causes the temperature to be too high, and the performance of the magnetorheological fluid 14 will decrease. Existing studies have shown that if the temperature of the magnetorheological fluid 14 is greater than 70°C, the shear yield stress of the magnetorheological fluid 14 decreases by 24%, resulting in a 19.8% decrease in the torque transmitted by the clutch. However, in this solution, under the action of high temperature, the shape memory alloy spring 17 stretches and exerts an extrusion force on the armature 5, and the armature 5 further squeezes the magnetorheological fluid 14, the active disc 10, the driven disc 11, the inner rubber ring 12, and the outer rubber ring 13, thereby further enhancing the extrusion strengthening effect. At the same time, the friction between the active disc 10, the driven disc 11 and the magnetorheological fluid 14 is increased, so that the shape memory alloy can compensate for the effect of the magnetorheological torque decrease caused by the increase in temperature, and the clutch torque can be stabilized. In this way, the transmission performance of the clutch under different temperature conditions is effectively guaranteed, so that the transmission performance of the clutch meets the use requirements.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A cross arc groove magnetorheological clutch squeezed by electromagnetic force, comprising a driving shaft, a driven housing and a driven shaft, characterized in that: The driven housing comprises a left housing, a driven cylinder, an armature and a blind cover, wherein the left housing is fixedly connected to the left end of the driven cylinder; the armature is located at the right end of the driven cylinder, and the middle part thereof protrudes to the right to form a sleeve, through which the armature is sleeved on the blind cover, and is connected with the blind cover in a sliding manner through the cooperation of a key and a key slot; on the left side of the armature, a plurality of guide shear rods are arranged around the position corresponding to the driven cylinder, and a guide hole is arranged on the right end face of the driven cylinder corresponding to the guide shear rod, one end of the guide shear rod is fixedly connected to the armature, and the other end extends into the guide hole and is connected in a sliding manner with the guide hole; on the left side of the armature, a plurality of return springs are also arranged around the position corresponding to the driven cylinder, and a spring groove is arranged on the right end face of the driven cylinder corresponding to the return spring, the return spring is located in the spring groove, one end of the return spring is fixedly connected to the bottom of the spring groove, and the other end extends out of the spring groove and is fixedly connected to the armature; A coil groove is provided in the middle of the inner side of the driven cylinder, and an excitation coil is wound in the coil groove; a magnetic isolation ring is provided on the inner side of the driven cylinder, the outer side of the magnetic isolation ring is in close contact with the inner side of the driven cylinder, the left end of the magnetic isolation ring is in close contact with the left shell, and the right end extends from the right end of the driven cylinder; a circular groove is provided on the left side of the armature corresponding to the magnetic isolation ring, and the depth of the circular groove is greater than or equal to the length of the magnetic isolation ring extending from the right end of the driven cylinder; the right end of the magnetic isolation ring extends into the circular groove and is connected with the groove wall of the circular groove in a sliding fit; The right end of the driving shaft passes through the left housing and then extends into the cover, and is connected to the left housing and the cover through a bearing; the part of the driving shaft located in the driven housing forms a transmission section, and a plurality of key grooves are arranged around the transmission section to form a spline shaft; a driving disc and a driven disc are sleeved on the transmission section, and the driving disc and the driven disc are alternately distributed along the axial direction of the driving shaft, and there is a gap between adjacent driving discs and driven discs, and there is also a gap between the driving disc or the driven disc and the left housing and the right housing; wherein the inner hole of the driving disc is a spline hole corresponding to the transmission section, and the driving disc is connected to the transmission section through the spline hole and can rotate synchronously with the driving shaft; the inner hole of the driven disc is a circular hole and can rotate freely around the driving shaft; a plurality of arc grooves are arranged on both sides of the driving disc and the driven disc, and the arc grooves are distributed on a plurality of circles centered on the center of the driving disc or the driven disc, and the adjacent two arc grooves distributed along the radial direction of the driving disc or the driven disc are arranged on the inner hole of the driven disc. The grooves are staggered; an inner rubber ring is provided between the active disk and the left housing, between two adjacent active disks, and between the active disk and the armature, respectively; the inner rubber ring is sleeved on the transmission section, and a gap is provided between the outer side of the inner rubber ring and the inner hole of the driven disk; an outer rubber ring is provided between the driven disk and the left housing, between two adjacent driven disks, and between the driven disk and the armature, respectively; the outer side of the outer rubber ring is in close contact with the magnetic isolation ring, and a gap is provided between the inner side and the outer edge of the active disk; the driven disk and the outer rubber ring are connected to the left housing through several connecting bolts that penetrate the outer rubber ring and the driven disk from right to left in sequence; the gaps between the left housing, the active disk, the driven disk, and the armature are filled with magnetorheological fluid; through holes for the screw rod of the connecting bolt to pass through are provided on the outer rubber ring and the driven disk at positions corresponding to the connecting bolts, wherein the through hole on the outer rubber ring between the driven disk and the armature is a countersunk hole, and the bolt head of the connecting bolt is located in the countersunk hole; The left end of the driven shaft is fixedly connected to the blind cover, and a support ring is also sleeved on the driven shaft, and the support ring is fixedly connected to the blind cover; a plurality of guide support rods are provided on the left side of the support ring, and the length direction of the guide support rods is consistent with the axial direction of the driving shaft; a shape memory alloy spring is sleeved on the guide support rod, and one end of the shape memory alloy spring is fixedly connected to the armature, and the other end is in contact with the support ring.

2. The cross arc groove magnetorheological clutch squeezed by electromagnetic force according to claim 1 is characterized in that: A brush slip ring is also arranged on the left side of the left housing. The brush slip ring is arranged coaxially with the driving shaft and is fixedly connected to the left housing. Both ends of the excitation coil are connected to the brush slip ring.

3. The cross arc groove magnetorheological clutch squeezed by electromagnetic force according to claim 1 is characterized in that: It also includes a dust cover, which is a cylindrical structure with one end open and the other end closed. The closed end of the dust cover has a mounting hole and is sleeved on the driven shaft through the mounting hole. The open end of the dust cover extends toward the driven cylinder and is sleeved on the driven cylinder.

4. The cross arc groove magnetorheological clutch with electromagnetic force extrusion according to claim 1 is characterized in that: A sealing ring is respectively arranged on the inner side of the two bearings. The sealing ring is sleeved on the driving shaft and seals the gap between the driving shaft and the left housing and the gap between the driving shaft and the blind cover.

5. The cross arc groove magnetorheological clutch squeezed by electromagnetic force according to claim 1, characterized in that: A sealing ring is also provided between the armature and the blind cover. The sealing ring is sleeved on the blind cover and fixedly connected to the blind cover.

6. The cross arc groove magnetorheological clutch of electromagnetic force extrusion according to claim 1 is characterized in that: A transparent cover is also arranged on the left side of the left shell body. The transparent cover is sleeved on the main shaft and fixedly connected to the left shell body. A felt ring is arranged between the transparent cover and the driving shaft.

7. The cross arc groove magnetorheological clutch with electromagnetic force extrusion according to claim 1 is characterized in that: A liquid injection hole is also arranged on the left shell body, and a liquid injection screw plug is matched in the liquid injection hole.

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